Factors associated with disease activity of pouchitis after surgery for ulcerative colitis.

BACKGROUND: Pouchitis occurs in 20% to 59% of patients operated on for ulcerative colitis. Several risk factors have been identified for the development of pouchitis. This study was undertaken to assess the incidence of pouchitis at least 5 years after ileal pouch-anal anastomosis for ulcerative colitis, and to evaluate possible predictive factors for inflammation activity. METHODS: A total of 107 subjects were enrolled (54 M, 53 F, mean age 45 years, range 23-69) with a J-pouch created between 1985 and 1994. Preoperative medical history was determined, an endoscopy performed, and biopsies taken from the pouch and neoterminal ileum above the pouch. Sera from all patients were tested for perinuclear antineutrophil cytoplasmic antibodies (pANCAs). RESULTS: After a mean 7.5-years' follow-up time, the cumulative incidence of pouchitis was 58%. Risk for development of active inflammation (PDAI > or = 7) was significantly higher in patients with preoperative extraintestinal manifestations (OR 2.7, 95% CI 1.1-6.4, P=0.03). Patients who had had ankylosing spondylitis (AS) (OR 11.7, P=0.006) or iritis (OR 9.8, P=0.013) were especially at risk. Positive titres of pANCAs were associated with inflammation in the neoterminal ileum; 80% of patients with high pANCA levels (>100) had pouchitis. Current smokers tended to have a more benign disease course. CONCLUSIONS: A correlation existed between the prevalence and titre of pANCAs and extent and disease activity of pouchitis. Chronic pouchitis may continuously stimulate the immunological process, keeping pANCAs at detectable levels. A strong correlation between AS, iritis and pouchitis suggests a common link in their pathogenesis.

Factors associated with ileal mucosal morphology and inflammation in patients with ileal pouch-anal anastomosis for ulcerative colitis.

PURPOSE: Pouchitis has been associated with abnormal bacterial flora responding to antibiotics. Dietary factors may play a role in modifying the qualitative and quantitative components of the microflora. We evaluated interactions between nutritional factors, fecal and mucosal bacterial flora, and mucosal morphology in patients with a history of pouchitis compared with patients with optimal outcome at least five years after ileal pouch-anal anastomosis for ulcerative colitis. METHODS: Thirty-two patients were enrolled in the study: 11 (7 males; mean age, 49.8 years) with optimal outcome and 21 (11 males; mean age, 47.3 years) with pouchitis history. A seven-day food diary was recorded, endoscopy performed, and biopsies taken from the pouch for histology, mucin staining, and bacterial culture. Fresh fecal samples were quantitatively cultured, and fecal bile acids analyzed by gas-liquid chromatography. RESULTS: No differences existed in mean nutrient intake, composition of fecal bile acids, or microbial tissue biopsy cultures between the groups with and without pouchitis. Those with optimal outcome tended to have more benign disease course of ulcerative colitis than patients with pouchitis. In those patients, fecal concentrations (log10 colony-forming unit/g) of anaerobes and aerobes were significantly higher (P = 0.007). Degree of villous atrophy and colonic metaplasia were both associated with fecal anaerobic flora. Low intake of lactose was associated with sulfomucin predominance. A negative correlation existed between fecal aerobes and dietary lactose consumption. CONCLUSIONS: A higher total load of fecal anaerobic bacterial flora is strongly associated with degree of colonic metaplasia, villous atrophy, and inflammation activity after surgery for ulcerative colitis. An association existed between dietary lactose, fecal bacteria, and pouch morphology. Lactose may have prebiotic properties.

Effect of Lactobacillus rhamnosus GG on ileal pouch inflammation and microbial flora.

BACKGROUND: Preliminary trials of probiotics in preventing recurrent chronic pouchitis have been encouraging. AIM: To investigate the efficacy of Lactobacillus GG supplementation as primary therapy for ileal pouch inflammation, and its effect on the microbial flora. METHODS: Twenty patients, with a previous history of pouchitis and endoscopic inflammation, were recruited for a prospective, randomized, double-blind, placebo-controlled trial of Lactobacillus GG supplementation (10 LGG, 10 placebo) in two gelatine capsules [(0.5-1) x 10(10) colony-forming units/capsule] b.d. for 3 months. Quantitative bacterial culture of fresh faecal samples and biopsies taken from the pouch and afferent limb was performed before and after supplementation. RESULTS: Lactobacillus GG supplementation changed the pouch intestinal flora by increasing the ratio of total faecal lactobacilli to total faecal anaerobes (P = 0.03) and enhancing the frequency of lactobacilli-positive cultures in the pouch and afferent limb mucosal biopsy samples. However, only 40% of patients were colonized with Lactobacillus GG. No differences were observed between the groups with regard to the mean pouchitis disease activity index or the total anaerobes or aerobes of faecal or tissue biopsy samples. CONCLUSIONS: A single-strain probiotic bacterium supplement of Lactobacillus GG changed the pouch intestinal bacterial flora, but was ineffective as primary therapy for a clinical or endoscopic response. More clinical trials are needed to evaluate the right placement and dosage of probiotics within a treatment regimen for pouchitis.

Risk of osteopenia after proctocolectomy and ileal pouch-anal anastomosis for ulcerative colitis.

BACKGROUND: The aim of our study was to evaluate the influence of pouchitis and villous atrophy on bone mineral density and metabolism at least 5 years after ileal pouch-anal anastomosis for ulcerative colitis (UC). METHODS: Eighty-eight subjects with a J-pouch operated on between 1985 and 1994, and 20 ulcerative colitis subjects with a conventional ileostomy were enrolled. Endoscopy was performed and spine and femoral neck bone mineral densities measured. Bone metabolism was assessed by measurement of serum levels of parathyroid hormone, osteocalcin, 25-hydroxyvitamin D3, calcium, alkaline phosphatase and urinary N-telopeptide cross-linked of type I collagen (NTX). RESULTS: In the lumbar spine, 37% of the J-pouch subjects with subtotal to total villous atrophy had osteopenia (Z score <-1), whereas none of the subjects with normal villous structure had reduced bone densities in the spine or femoral neck. The highest prevalence of osteopenia (66.7%) and the lowest spine (mean -0.89+/-0.36; P = 0.006) and femoral neck (mean -0.63+/-0.29; P = 0.07) Z scores were found among the patients (n = 12) with inflammation in the proximal limb of the pouch. No biochemical parameters were found to predict osteopenia and in stepwise regression analysis, the only independent risk factors for osteopenia were low body mass index and villous atrophy. CONCLUSIONS: Patients with a J-pouch showing high inflammatory activity and villous atrophy in the pouch need long-term follow-up and should be ensured adequate intake of calcium and vitamin D.

Long term metabolic consequences of ileal pouch-anal anastomosis for ulcerative colitis.

OBJECTIVES: Chronic inflammation in the ileal pouch is the most significant late complication after ileal pouch-anal anastomosis (IPAA). It leads to changes in mucosal morphology, with consequent decreased vitamin B12, bile acid and cholesterol absorption documented. The aims of this study were to evaluate long term metabolic consequences at least 5 yr after IPAA and the influence of pouchitis on pouch histology and on bile acid, lipid, and vitamin B12, A, E, and D metabolism. METHODS: A total of 104 patients with a J-pouch who were operated on between 1985 and 1994, as well as 21 ulcerative colitis patients with a conventional ileostomy were enrolled for the study. Routine blood tests, vitamin status, vitamin B12 levels, and bile acid absorption were determined, as well as endoscopy with biopsies. The pouchitis disease activity index (PDAI) was calculated. On the basis of histology, IPAA patients were divided into three subgroups: 1) those with no villous atrophy, 2) those with partial villous atrophy, and 3) those with subtotal or total villous atrophy. RESULTS: Incidence of pouchitis was 42.3%, and was strongly associated with villous atrophy. In IPAA patients with subtotal or total villous atrophy (32.7%), serum levels of albumin, calcium, total cholesterol, triglycerides, and vitamin E were significantly reduced (p < 0.05). The lowest bile acid and vitamin B12 absorption rates were seen in patients with inflammation in the proximal limb. Vitamin D deficiency was seen in 10.6%, and vitamin A and B12 deficiency in approximately 5% of IPAA patients. CONCLUSIONS: Metabolic consequences after IPAA are associated with pouchitis, grade of villous atrophy, and extent of inflammation in the remaining ileum. Patients with active chronic inflammation need long term follow-up.

Intestinal type of thromboangiitis obliterans (Buerger disease) preceding symptoms of severe peripheral arterial disease.

The case of a 50-year-old man with intestinal type thromboangiitis obliterans (Buerger disease) is reported. Intestinal manifestations included stricture and perforation of the colon, and these preceded any symptoms of peripheral vascular disease. Only the histological examination was able to show that our patient had the intestinal type of thromboangiitis obliterans.

Duodenal disaccharidase activities in the follow-up of villous atrophy in coeliac disease.

BACKGROUND: In active coeliac disease, mucosal atrophy is associated with a marked decrease in intestinal disaccharidase enzyme activities. We investigated the value of duodenal mucosal disaccharidases to predict the severity of mucosal villous atrophy and its recovery in 50 patients with coeliac disease. METHODS: Duodenal mucosal histology and disaccharidase activities were studied at least twice with a mean interval of 9 months. Histology of specimens from all patients was examined by the same pathologist blinded to the data on disaccharidase activities. Mucosal damage was scored into four groups as follows: Grade 0 = normal mucosa; grade I = slight villous atrophy, that is, cryptic component 30%-50%; grade 2 = moderate villous atrophy, that is, cryptic component 50%-90%; grade 3 = severe villous atrophy, that is, cryptic component >90%. The enzyme activities of the disaccharidases were determined as U/g protein. RESULTS: Duodenal mucosal disaccharidase activities were good predictors of the grade of mucosal villous atrophy. Positive predictive values for moderate or severe villous atrophy were 90% for maltase (maltase activity <150 U/g protein), 86% for sucrase (<40 U/g protein) and 71% for lactase (<20 U/g protein). Accordingly, negative predictive values, that is, none or only minimal villous atrophy (grades 0 or 1) with normal disaccharidase activities, were 71% for maltase, 70% for sucrase and 63% for lactase. CONCLUSIONS: The increase in duodenal disaccharidase activities correlated with recovery of the mucosa based on histology. Besides the histological examination, measurement of disaccharidase activities offers an additional tool to evaluate response to a gluten-free diet in patients with coeliac disease.

Inhibin/activin betaB-subunit expression in pheochromocytomas favors benign diagnosis.

Malignancy of pheochromocytomas is difficult to estimate on the basis of histopathological features. Good prognostic markers are not available. In our search for new markers to differentiate malignant pheochromocytomas from benign ones we tested the value of inhibin/activin subunit expression. Inhibins are heterodimeric glycoproteins consisting of an alpha-subunit and either a betaA- or a betaB-subunit. Activins are composed of beta-subunits only. Immunohistochemically inhibin/activin betaB-subunit was strongly positive in the normal adrenal medulla, but the cortex was negative. A striking difference was found in inhibin/activin betaB expression between benign and malignant pheochromocytomas. The majority of benign adrenal tumors (27 of 30) showed strong or moderate immunoreactivity, whereas all seven malignant tumors were negative or only weakly positive for inhibin/activin betaB-subunit. The percentage of positively staining cells varied greatly in extraadrenal pheochromocytomas and in those benign tumors that showed over 5 mitoses/10 high power fields, necrosis, or capsular or vascular invasion, here called borderline tumors. Inhibin/activin betaB messenger ribonucleic acid was also found in pheochromocytomas. However, no significant differences in messenger ribonucleic acid levels were found in various types of tumors. Weak immunohistochemical positivity for inhibin/activin betaA-subunit was detected in the adrenal cortex, but the medulla and most of the pheochromocytomas were negative. Our data show that inhibin/activin betaB-subunit is expressed in normal adrenal medullary cells. Strong staining is found in most benign adrenal pheochromocytomas, whereas malignant tumors are almost negative. This suggests that loss of inhibin/activin betaB-subunit expression in pheochromocytomas may be used as an indicator of malignant potential.

Expression of low and high density lipoprotein receptor genes in human adrenals.

Corticosteroids are synthesized from cholesterol which may arise from de novo synthesis or from the uptake of low or high density lipoproteins (LDL or HDL). In the present study, we compared the expression and regulation patterns of LDL receptor and CLA-1 (CD36 and LIMPII Analogous-1, an HDL receptor) genes in adult human adrenocortical tissues to shed more light on the relative contribution of LDL and HDL in human adrenal steroidogenesis. By screening 64 normal and pathological adrenal samples by Northern blotting, we found a positive correlation between LDL receptor and CLA-1 mRNA expression in the adrenal tissues (r=0.547; spearman rank correlation test P<0.01). Adrenal tissues adjacent to Cushing's adenomas contained consistently less LDL receptor and CLA-1 mRNA than normal adrenals (Mann-Whitney P<0.05). In primary cultures of normal adrenal cells, accumulation of both LDL receptor and CLA-1 mRNAs was upregulated by ACTH in a dose- and time-dependent manner, with an earlier induction of LDL receptor than CLA-1 mRNA expression. (Bu)(2)cAMP also increased the levels of these two mRNAs. Addition of LDL, but not HDL, into the culture medium increased cortisol production in untreated adrenocortical cells. Both LDL and HDL enhanced ACTH-induced cortisol production, with the effect of LDL much stronger than that of HDL. Our data show that LDL receptor and CLA-1's expression is ACTH-dependent and occurs in parallel in human adrenal tissues. LDL rather than HDL may be used as the preferential source of cholesterol for steroidogenesis in human adult adrenocortical cells.

Expression of inhibin alpha in adrenocortical tumours reflects the hormonal status of the neoplasm.

Inhibins are gonadal glycoprotein hormones whose main endocrine function is to inhibit pituitary FSH secretion. In addition to testes and ovaries, other steroid-producing organs are sites of inhibin alpha subunit expression. To study the role of inhibins in human adrenal gland, we screened a panel of 150 adrenals (10 normal adrenals, 25 adrenocortical hyperplasias, 65 adrenocortical adenomas, 30 adrenocortical carcinomas and 20 phaeochromocytomas) for inhibin alpha expression. mRNA levels of inhibin alpha subunit were studied in 57 samples and all tissues were stained immunohistochemically with an inhibin alpha subunit-specific antibody. Inhibin alpha mRNA was detected in all adrenocortical tissues. Virilizing adenomas possessed a 10-fold higher median inhibin alpha mRNA expression than did normal adrenals. Bilaterally and nodularly hyperplastic adrenals and other than virilizing adrenocortical tumours had their median inhibin alpha mRNA levels close to those of normal adrenals. Immunohistochemically, inhibin alpha subunit was detectable in all normal and hyperplastic adrenals, as well as in 73% of the adrenocortical tumours. However, the percentage of inhibin alpha-positive cells varied greatly in different tumour types. The median percentage of positive cells was 10 in non-functional and Conn's adenomas, 30 in Cushing's adenomas and 75 in virilizing adenomas. In malignant adrenocortical tumours the median percentage of inhibin alpha-immunopositive cells was 20 in non-functional carcinomas, 30 in Conn's carcinomas, 65 in Cushing's carcinomas and 75 in virilizing carcinomas. All phaeochromocytomas were negative for inhibin alpha subunit both at the mRNA level and immunohistochemically. Our data show that inhibin alpha subunit is highly expressed in both normal and neoplastic androgen-producing adrenocortical cells, with less expression in cortisol-producing and hardly any in aldosterone-producing cells. This suggests a specific role for inhibins in the regulation of adrenal androgen production. We did not find any significant difference in inhibin alpha expression between benign and malignant adrenocortical tumours. Thus inhibin alpha gene does not seem to have a tumour suppressor role in human adrenal cortex.

Expression of activin A and its receptors in human pheochromocytomas.

Activin A (a homodimer of two activin betaA subunits) has been shown to induce the neuronal differentiation of rat pheochromocytoma PC12 cells. We studied activin A and its receptor gene expression in human pheochromocytomas in vivo and in vitro to clarify the potential involvement of activin A in the pathophysiology of these tumors. We first screened 20 pheochromocytomas and nine normal adrenal tissues for activin betaA mRNA expression. Northern blots hybridized with specific oligonucleotide probes detected weak signals for activin betaA transcripts in pheochromocytomas. Both type I and type II activin receptor (ActR-I, ActR-IB and ActR-II) mRNA expression was also detectable in the pheochromocytoma tissues. In primary cultures of pheochromocytoma cells, expression of activin betaA mRNA was readily detectable by Northern blotting, and secretion of activin A into the conditioned medium was confirmed by an enzyme-linked immunosorbent assay. The expression of activin betaA mRNA and secretion of activin A were induced by (Bu)(2)cAMP after 1 and 3 days of treatment (all P<0.05). A protein kinase inhibitor, staurosporine, inhibited the basal and (Bu)(2)cAMP-induced accumulation of activin betaA mRNA (P<0.05). In addition, induction of chromaffin phenotype by dexamethasone also inhibited the basal and (Bu)(2)cAMP-induced expression of activin A at both mRNA and protein levels (all P<0.05). In contrast, the expression of ActR-I and ActR-IB mRNAs was not affected by these agents in cultured pheochromocytoma cells. In summary, activin betaA subunit and activin receptors are expressed in human pheochromocytomas. Production of activin A in cultured pheochromocytoma cells is induced through the protein kinase A pathway, but reduced during chromaffin differentiation. Therefore, activin A may function as a local neurotrophic factor via an auto/paracrine manner in human pheochromocytomas.

p53 and Ki67 in adrenocortical tumors.

The p53 tumor-supressor gene has been reported as the most frequent genetic abnormality seen in human malignancies. Here we studied immunohistochemically the expression of p53 in a large series of adrenocortical tumors. The proliferative activity was assessed by the expression of Ki67. Tumor material consisted of 60 adrenocortical adenomas and 27 adrenocortical carcinomas. A tumor was scored as positive for p53 if more than 10% of the cells showed nuclear staining. All adrenocortical adenomas were negative for p53 and the percentage of Ki67 positive cells was mostly 1-2% but never exceeded 5%. Hormonal activity did not reflect the proliferation index. Adrenocortical carcinomas, however, behaved differently depending on hormonal activity. 10/13 of non-functional , 0/3 Conn's, 3/7 Cushing's and 3/4 virilizing carcinomas were positive for p53. The proliferative activity was also higher in non-fuctional carcinomas compared with hormonally active tumors. Our data show that majority of adrenocortical carcinomas are positive for p53, whereas all adenomas are negative. Hormonal activity of carcinomas reflects both p53 status and proliferation index. Thus, immunohistochemical levels of p53 and Ki67 are higher in hormonally inactive adrenocortical carcinomas.

Expression of vascular endothelial growth factor in human adrenals.

Angiogenesis is an important component in many biological processes and also in pathologic conditions including neoplastic diseases. Vascular endothelial growth factor (VEGF) is a secreted endothelial cell-specific growth factor, which is induced by tissue hypoxia and is angiogenic in vivo. Adrenal gland is a well-vascularized organ, and the roles of VEGF in normal adrenal and in adrenal tumorigenesis is not well characterized. We therefore investigated VEGF mRNA expression in normal human adrenals and in cultured adrenocortical cells. VEGF mRNA was constantly expressed in normal adrenals as well as in cultured adrenocortical cells. The mRNA levels were increased after 24h stimulation with either ACTH or cAMP. The effect of cAMP was dose-dependent. This suggests that ACTH-induced VEGF mRNA expression is mediated via protein kinase A dependent pathway.

Regulation of neuropeptide Y mRNA expression in cultured human pheochromocytoma cells.

The expression of the neuropeptide Y (NPY) gene varies considerably in human pheochromocytomas, but the mechanisms for this variation have not been clarified. To investigate the regulation pattern of the NPY gene in human pheochromocytomas, we screened 16 pheochromocytomas and 9 normal adrenal tissues with Northern blots. The expression level of NPY mRNA in normal adrenal medulla was low and relatively constant, while the pheochromocytomas showed a very wide variation in NPY mRNA levels in both malignant and benign tumors. This indicates that NPY gene expression is not correlated with malignancy in pheochromocytomas. In primary cultures of human pheochromocytoma cells, nerve growth factor treatment (causing neuronal differentiation) increased NPY mRNA accumulation 2- to 5-fold (P < 0.05). NPY mRNA levels were also induced by protein kinase modulators (Bu)(2)cAMP and staurosporine in the cultures (P < 0.05). In contrast, treatment with dexamethasone and IGF-II (causing or linked with chromaffin differentiation) reduced NPY mRNA accumulation (P < 0.05). These data show that the regulation pattern of NPY mRNA expression in cultured human pheochromocytoma cells is different from that previously described in rat pheochromocytoma PC12 cells. Regulation of NPY mRNA expression in primary cultures by these differentiating factors suggests that the expression of NPY mRNA in pheochromocytoma tissues may be associated with the neuronal differentiation of the tumor cells affected by multiple factors.

pG2 gene expression and its regulation in human adrenocortical and medullary tumors.

The cDNA clone pG2 was originally isolated from a human pheochromocytoma. The respective gene was found to be strongly expressed in normal adrenal zona glomerulosa and medulla, as well as in Conn's adenomas and pheochromocytomas. To shed more light on the expression and regulation of the pG2 gene, we investigated its expression in a wide variety of different adrenal neoplasms and cultured adrenal cells. Northern blot analysis was used to determine the steady state level of pG2 mRNA. Besides normal adrenals, Conn's adenomas and pheochromocytomas, we found abundant expression of pG2 mRNA in Cushing's, virilizing and nonfunctional adrenocortical adenomas and carcinomas, as well as in hyperplastic adrenals. The relative levels of pG2 mRNA in various adrenocortical tumors were not significantly different from those in normal adrenals and pheochromocytomas. In primary cultures of normal adrenal cells, treatment with adrenocorticotropin induced a 3- to 15-fold increase in the expression of pG2 mRNA (P<0.01), and this effect was reproduced by incubation with (Bu)2cAMP. In cultured pheochromocytoma cells, treatment with (Bu)2cAMP and a protein kinase inhibitor, staurosporine, increased pG2 mRNA accumulation (2- to 4-fold over the control level, P<0.01, and 3- to 8-fold, P<0.01, respectively). These results indicate that pG2 is widely expressed in normal and pathological adrenal tissues from both cortical and medullary origin, which eliminates its usefulness as a specific marker for zona glomerulosa or medullary adrenal tumors. Accumulation of pG2 mRNA is regulated by multiple differentiating factors through different pathways in primary cultures of normal adrenal and pheochromocytoma cells.

Expression of insulin-like growth factor binding protein 1-6 genes in adrenocortical tumors and pheochromocytomas.

The insulin-like growth factor (IGF) system appears to be important in the regulation of adrenal growth and hormone synthesis. As IGF-binding proteins (IGFBPs) modify IGF bioactivity, we investigated the expression of IGFBP 1-6 genes in different adrenal tumors and hyperplasias to further clarify the role of the IGF system in adrenal pathophysiology. IGFBP-1 mRNA levels were too low to be detected by Northern blot analysis, but could be found by RT-PCR in some tumors and hyperplastic adrenals. Other IGFBPs were detected by Northern blotting. IGFBP-3 mRNA levels were very low in normal adrenals. In adrenal tumors and hyperplastic adrenals, IGFBP-3 mRNA expression was usually higher than in normal adrenals. In hormonally active adrenocortical carcinomas, IGFBP-2, -4, -5 and -6 mRNA levels were lower than in nonfunctional carcinomas and normal adrenals. The low IGFBP mRNA expression in the hormone-producing carcinomas was associated with high IGF-II mRNA content. In adrenocortical adenomas from patients with Cushing's or Conn's syndrome, mean IGFBP mRNA levels were higher than in normal adrenals or in hormonally inactive adenomas. In nodular and bilateral hyperplasias, IGFBP-2, -3 and -4 mRNA expression was on average higher than in normal adrenals but varied substantially, as did IGFBP mRNA levels in pheochromocytomas. In comparison to normal adrenals, pheochromocytomas expressed on average higher levels of IGFBP-2 and -4 but less IGFBP-5 and -6 mRNAs. Our data show that the six IGFBPs 1-6 are expressed at variable level in adrenal tumors and hyperplasias. The low level of IGFBP mRNAs in hormonally active adrenocortical carcinomas was of particular interest.

ACTH regulates LDL receptor and CLA-1 mRNA in the rat adrenal cortex.

Rat adrenocortical cells utilize both low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol for steroid hormone production. In addition to exogenous lipoprotein-derived cholesterol, cells produce cholesterol de novo. Adrenocorticotropin (ACTH) increases both steroid hormone secretion and uptake of LDL and HDL. We studied the expression of LDL receptor mRNA and CLA-1 (a putative HDL receptor) mRNA in cultured rat adrenocortical cells. ACTH increased the amounts of LDL receptor mRNA during 2 to 48 h of stimulation, the highest levels being detected after 2-4 h. Similar results were obtained with cyclic AMP (cAMP) derivatives, 8-bromo cAMP (8-Br cAMP) or dibutyryl cAMP. ACTH increased CLA-1 mRNA during 2 to 24 h of stimulation, the highest levels being detected after 4 h. In conclusion, ACTH up regulates both LDL and HDL receptor mRNA in rat adrenocortical cells.

Expression of inhibin alpha in the human adrenal gland and adrenocortical tumors.

We studied the expression of inhibin alpha-subunit in normal and hyperplastic adrenal glands, as well as in various adrenocortical tumors. The protein expression of inhibin alpha was performed by immunohistochemistry. Virilizing adenomas showed strong immunoreactivity against monoclonal inhibin alpha-subunit antibody, whereas other adenomas were only weakly positive or completely negative. In the adrenal cortex no inhibin alpha immunoreactivity was detected in the zona glomerulosa. Zona fasciculata showed weak staining for inhibin alpha, however, strong immunostaining was detected in zona reticularis both in normal and hyperplastic adrenal glands. Adrenal medulla was negative for inhibin alpha. In conclusion, we show high expression of inhibin alpha subunit in zona reticularis of normal and hyperplastic adrenal glands as well as strong expression in virilizing adenomas.

Ribonucleic acid expression of the CLA-1 gene, a human homolog to mouse high density lipoprotein receptor SR-BI, in human adrenal tumors and cultured adrenal cells.

Human CLA-1 is homologous to the mouse SR-BI gene, which was recently identified as a high density lipoprotein receptor involved in selective cholesterol uptake in rodent adrenal cells. We screened 42 normal and pathological adrenal samples by Northern blotting and found abundant expression of CLA-1 messenger ribonucleic acid (mRNA) in normal adult and fetal adrenals, adrenocortical adenomas, and hyperplasias. Adrenocortical carcinomas and the adrenals adjacent to Cushing's adenomas contained less CLA-1 mRNA than normal adrenals. CLA-1 mRNA was also highly expressed in a Leydig cell tumor, but much less in liver, kidney, and pheochromocytomas. The accumulation of CLA-1 mRNA in primary cultures of normal adrenocortical cells was up-regulated by ACTH in a dose- and time-dependent manner. Both dibutyryl cAMP and staurosporine increased the basal expression of CLA-1 mRNA. Although there was no additive effect of ACTH and dibutyryl cAMP, staurosporine slightly enhanced the stimulatory effect of ACTH on the expression of CLA-1 mRNA. The abundant expression of CLA-1 mRNA and its regulation by the physiological hormone ACTH in human adrenal cells suggest that CLA-1 has a role in adrenal steroidogenesis, probably as a lipoprotein receptor mediating the selective cholesterol uptake in these cells.